Add header information and documentation.
Fix bug in input file path parsing.
Add test *.sle file to extract MD box size.
Add *.sle extraction of MD box size into *.h5 file.

Add a table in the MD simulation parameters table to hold the (x,y,z) box size
for the simulation. This information is read off of the *.sle file. Currently
the parsing is hardcoded, and it is expected that a *.sle file with the same
filename is in the directory with the *.xvg file.
Merge branch 'hdf5-prototyping' into develop